Status 4.5W MR16

Lamps and bulbs are the replaceable light sources in ceiling lights, lamps, spotlights, appliances and fluorescent fittings. Most of the range is LED, in shapes such as GLS, candle, golf ball, globe, spot, capsule and tube.

Find the right cap

• B22 (bayonet cap, BC): a 22mm cap that pushes in and twists to lock.
• E27 (Edison screw, ES) and E14 (small Edison screw, SES): screw-in caps in two sizes; check which the holder takes.
• GU10: mains-voltage spotlight with a twist-and-lock base.
• MR16 (GU5.3): low-voltage 12V spotlight with thin pins that needs a transformer. It is not interchangeable with GU10.
• G9, G4 and G23: capsule and plug-in caps for compact fittings and appliances.

Brightness and colour

Choose by lumens, not watts: lumens measure brightness, while watts measure the power used. Colour temperature is given in kelvin (K). Warm white, around 2700K to 3000K, suits most rooms in a home; higher figures such as 4000K and 6500K (daylight) give a cooler, whiter light. Lamps are marked dimmable or non-dimmable, so check this if the light is on a dimmer switch.

LED tubes

LED replacements for fluorescent tubes are made for particular types of control gear: conventional (electromagnetic), electronic (high frequency) or direct mains wiring. Check which the fitting has before choosing. Rewiring a fitting, and new fixed wiring or work in bathrooms, should be done by a registered competent person; some of it is notifiable under Part P of the Building Regulations.

For light fittings, see lighting; for switches and sockets, see electrical accessories.